Slate in the Shower

Q.My client wants to install
slate tile in her shower to match the tile on her
bathroom floor. I know that slate is porous and harder
to keep clean than ceramic tile, but is there a good
sealer that can be used with the slate so that
maintenance will be manageable?

A.Contributing editor
Michael Byrne, a tile-setter and consultant in Los
Olivos, Calif., and moderator of JLC Online's tile
forum, responds: The quality and density of
slate can vary quite a bit. Honed slate tiles dense
enough to be exposed to water don't absorb sealers
readily, whereas some softer slates with cleft
finishes will actually start disintegrating in
water.

And while not all penetrating sealers perform
well with slate, top-coating sealers can lead to
disaster when they yellow and begin to chip
off.

Generally speaking, I think that most tiles made
from porous stones like slate and limestone are a
bad choice in a shower stall. Regardless of the
type of sealer used or how often it's applied,
keeping slate or limestone in a sanitary condition
is almost impossible, as is removing the "dirty
clothes" smell that these stones tend to
accumulate.

Porcelain-tile look-alikes might appear to be
the first and best alternative, but they have their
problems too. Some of these tiles have a coarse
texture meant to make them slip-resistant;
unfortunately, it also allows dirt, grime, grease,
soap, and oils to lodge permanently on the tiles'
surface.

For best results, choose a smooth-surface stone
tile with absorption properties similar to those of
vitreous or impervious tiles — and avoid
any stones that require topical applications to
achieve these desired properties.